Reamer-stabilizer



Dec. 23, 1958 J. CHADDERDON 2,865,505

'REAMERPSTABILIZER Filed 001:. 4. 1954 5 Sheets-Sheet 1 IN V EN TOR.

JACK CHADDEPDO/V Dec. 23, 1958 J. CHADDVERDO'N 2,865,605

REAMER-STABILIZER Fil'ed Oct. 4, 1954 5 Sheets-Sheet 2 Z7 Z6 7 J .250 24 INVENTOR. JACK (Maui/$00M ATTORNEY 5 Sheets-Sheet 5 Filed Oct. 4, 1954 INVENTOR. J4c/ CHADDEEDOA/ A TTOE/VEY United States Patent 3 Claims. (Cl. 255-28) Long Beach, Calif., assignor to Servco Ltd, Long Beach, Calif., a corporation of This invention relates to a tool for use on a drilling string and combines both reaming and stabilizing features.

In rotary well drilling, one or more of several things may occur to form an impediment to upward retraction of the drill string when the same is desired. For instance, especially in deeper holes, flexure or lateral whip in the drill string will form a seat in the side-of the well bore that, in most cases, is smaller in diameter'than the drill collar. Or, if reamers are used, the same may become wedged. Or, there may be a collapse of the side of the bore around the drill string. The present tool is devised to cut through such obstruction so the string may be withdrawn.

In addition to the foregoing, the present tool serves as a stabilizer to prevent or greatly minimize dog legs in the bore, to keep the bore straight, to straighten crooked bores, to prevent or greatly minimize drill collar connection failure and/or wear, to maintain the angle of drift in directional drilling, to serve as a fulcrum above the drill bit to control the drift angle in directional drilling, etc.

It is an object of this invention to provide a reamerstabilizer tool that has the properties and functions above listed.

The invention also has for its objects to provide such means that are positive in operation, convenient in use, easily installed in a working position and easily disconnected therefrom, economical of manufacture, relatively simple, and of general superiority and serviceability.

The invention also comprises novel details of construction and novel combinations and arrangements of parts, which will more fully appear in the course of the following description. However, the drawings merely show and the following description merely describes, preferred embodiments of the present invention, which are given by way of illustration or example only.

In the drawings, like reference characters designate similar parts in the several views.

Fig. l is a side elevational view, partly in section, of a tool according to the present invention.

Fig. 2 is a cross-sectional view as taken on line2-2 of Fig. 1.

Fig. 3 is a broken view similar to Fig". l and showing said tool in another position.

Figs. 4, 5 and 6 are views respectively similar to Figs.

, 1, 2 and 3 of a modification.

Fig. 7 is an enlarged fragmentary sectional View of a reaming rib used in the invention.

Fig. 8 is a small-scale vertical elevational view of the lower portion of a drill string disposed in a well bore, said view showing a plurality of stabilizers to maintain straightness of the bore.

Fig. 9 is a similar view showing the arrangement for controlling the angle of drift of a slanted or directional bore.

Fig. 10 is another and similar view showing use of the present stabilizer arranged to straighten crooked holes.

The tool that is illustrated in the drawings comprises,

2,865,605 Patented Dec. 23, 19 58 generally, a mandrel 10, a sliding sleeve 11 mounted on said mandrel, a set of stabilizer and reaming ribs or fins 12 carried by said sleeve, and means 13 interconnecting the mandrel and sleeve to impart a jarring action between the mandrel and sleeve.

The mandrel 10 preferably comprises an integral memher that has a stem 14 intermediate end collars 15 and 16, the latter having end shoulder faces 17 and 18, respectively, which comprise abutments for the respective ends 19 and 20 of the sleeve 11. The upper collar 15 is shown with a threaded box 21 and depending from the collar 16 is a threaded pin 22. The collars 15 and 16 may be round or any desired polygonal shape. The stem 14, however, is preferably cylindrical to loosely rotationally and slidingly fit Within sleeve 11.

The above-described mandrel is adapted to be embodied into a drill string as an element of said string by entering the downwardly directed pin of a drill collar thereabove into box 21 and entering pin 22 in the box of a similar drill collar therebelow. It will be clear that said mandrel may be placed where desired in a drill string, and that more than one may be embodied in a string. If desired, the mandrel may be connected directly to the drill collar so as to comprise the lowermost element of a drill string above the bit.

The sleeve 11 has a cylindrical bore 23 that fits over stem 14, as above indicated, and is substantially shorter than said stem. The external diameter of said sleeve is substantially that of collars 15 and 16. As can be seen from Fig. 2, the collar is mounted on the mandrel by forming the same of longitudinal halves 24 that are permanently joined along their longitudinal edges by suitable welds 25, substantially as shown. As shown, the stabilizer sleeve 11 is relatively short having a length less than twice its diameter in the embodiment illustrated. This facilitates stabilizing in bore slant control and improves fulcrum action.

The mandrel and sleeve are both made of hard, longwearing material, of which steel is preferred.

The set of reaming ribs or fins 12 are preferably arranged on a right-hand pitch so as to ream the sides of a bore during the usual right-hand (clockwise, as viewed from above) rotation of the drill string and the drill collar and bit. As shown, a three-thread set of ribs may be welded to the outer face of the sleeve after the same has been assembled onto stem 14. The outer diameter of the three ribs 26 thus provided is substantially larger than that of the sleeve 11, so as to ream the bore produced by said bit. For this purpose, the outer faces 27 are hard-faced by providing the same with a layer or facing of hard material, such as tungsten-carbide or the ike.

1 Althoughthe hard face 27 is desired for reaming purposes, the ribs 26 themselves are preferably relatively soft, crumbly or machinable. Therefore, the same are made of ductile iron, at relatively new material having good structural strength but easily machinable so as to be readily removed, as by a rotary shoe or similar tool applied from above.

As shown in the form of Figs. 1, 2 and 3, the means 13 comprises similar oppositely arranged projections or keys 28 on the outer face of stem 14 midway between shoulders 17 and 18, two pairs of windows 29 and 30 formed in sleeve 11 and cooperating with said keys, and longitudinal passages 31 connecting the windows and of a size to pass the keys from one pair of windows to the other pair. I

The keys 28 are relatively shallower than the thickness of wall of sleeve 11, as can be seen in Fig. 2, the passage 31, therefore, being in the inner face of said sleeve leaving outer connecting walls 32 that enclose said passages.

Assuming normal rotation of the string and of mandrel 10 in the clockwise direction of arrow 33, the keys 28 are each provided on their left sides with respectively lower and upper sloping edge faces 34 and 35. Said faces are preferably at 45", but may be somewhat steeper, if deslred. The opposite edge face 36 of each key may he longitudinal, as shown.

The two pairs of windows are alike and each window of each pair is provided with sloping edge faces that are designed to engage the sloping faces of the keys. Thus, the upper pair of windows 29 are each provided with edge faces 37 and 38, respectively engageable by key edges 34 and 35. Similarly, the windows 30 are each provided with edge faces 39 and 40 adapted to be engaged by the same edges of the keys.

Operation During normal drilling, the abutments 17 and 19' are engaged since the string is moving downward as the drill bit bores into the hole. The keys 28, beingengaged with the edges 39 and 40 of windows 30, drive sleeve 11 so its ribs 26 ream the hole being drilled. Any such reamers placed in intermediate parts of the drill string will carry out the objects of the invention insofar as keeping the hole straight, preventing dog legs, etc.

If, at any time, it is necessary to dislodge the tool from any obstruction in or malformation of the hole that results in a seizure of the sleeve preventing either its rotation or movement longitudinally in the hole, jarring is resorted to. For instance, when coming out of a hole, if sleeve 11 is seized and shoulders 18 and 20 are abutted, as in Fig. 1, torsion is imparted to the drill string from above in the direction of arrow 33, causing the keys 28 to bear against window edges 37 and 38. Now, as the tension on the string is slacked off, its weight will cause the same to lower from the position of Fig. l to the position of Fig. 3, wherein edges 34 and 37 are slidingly engaged. Thus, the force of the torsion or the camming action between faces 34 and 37 will either free the sleeve or the keys will lose contact with faces 37 and drop suddenly through passages 31 into windows 30. When this occurs, the shoulder 17 of the mandrel strikes sleeve end 19 with a force that-is equal to the weight of the drill string and, at the same time, the keys are rotated clockwise to strike edge faces 39 and 40 of the lower windows 30 to impart rotation to the sleeve by the tor sion force stored up in the drill string. Thus, the sleeve is simultaneously subject to both a downward and a rotational thrust which, if great enough, will dislodge the sleeve from its point of seizure. If it is necessary to repeat the above action, the string is first released from torsion and then elevated to again bring the keys into windows 29. Now, the jarring action from above may be repeated.

When entering the string into a hole, so that sleeve 11 is seized with shoulders 17 and 19 abutted, torsion in the direction of arrow 33 is applied to the string to bring the keys 28 into engagement with the edge faces 39 and 40. Now, as the string is raised and a camrning action occurs between faces 35 and 40, the keys are drawn upwardly through passages 31. Since this engagement of keys 28 and faces 40 places a load, in addition to the weight of the string, on the mechanism that is raising the latter, when the keys are cammed past faces 40, the string will raise rapidly and shoulder 18 will strike sleeve end 20 while, at the same time, the torsion on the string is effective to rotate the sleeve, as before described. A repeat operation, if needed, may be elfected as described in connection with jarring from above.

It will be clear that jarring from above or below may be had as desired; that repeated jarring in the same direction may be performed; and that alternate up and down jarring may be efiected, as desired.

The tool illustrated in Figs. 4, and 6 is the same as 4 aha; tool above described except that the means 13 is modi- In this modification, the opposite projections or keys are disposed centrally on the stem between shoulders 17 and 18 and are symmetrically formed both on longitudinal and transverse axes and are each provided with edge faces 46, 47, 48 and 49 comparable to the 45 faces of keys 28. Thus, each key has upper and lower 45 faces on both sides of a medial line.

The sleeve 11 is provided with only one pair of windows 50 but each window, instead of upper and lower cam edge faces on one side, as in the earlier-described form, has upper and lower cam faces 51 and 52 on one side and similar faces 53 and 54 on the opposite side. Thus, each window 50 is defined by edge faces that give the same an octagonal form.

A passage 55 extends from the top of each window to the end 19 of sleeve 11 and a similar passage 56 extends from the bottom of each said window to the sleeve end 20.

Operation During normal drilling, shoulders 17 and 19 are engaged and the keys 45 reside in passages 56, in the same position that they reside in passages 55, as shown in Fig. 4, and the reaming sleeve is rotated by said keys in the direction of arrow 33.

If the sleeve becomes seized, torsion is applied to the string and the same raised to first bring the keys into windows 50 and then raised further to create a camming engagement between key faces 47 and window faces 51. Raising of the string is continued until the resistance of said camming faces is released by the keys entering passages 55. When this occurs, the force raising the string is eifective to bring shoulder 18 sharply against sleeve end 20. Since keys 45 remain in passages 55, the torsion of the string is effective on the sleeve simultaneously with the jar between abutments 18 and 20.

Reverse jarring, as illustrated, brings edge faces 46 of the keys and 52 of the windows into operation and utilizes the weight of the torsioned string as hereinbefore described.

In cases where the drilling string above terminates in a box rather than a pin, the tool of the modification may be reversed endfor-end and installed in the string with pin 22 upwardly directed into said box in the lower end of the string. In such case, the respective edges 48 and 49 of the keys and 53 and 54 of the window cooperate to effect either upward or downward jarring in exactly the manner above described.

Hence, the tool shown in the modification can do everything that the tool of Figs. 1, 2 and 3 can do and, in addition, can be installed up end down and function with equal facility.

The dot-dash lines of Figs. 3 and 6 represent the reaming ribs shown respectively in Figs. 1 and 4.

As indicated in the objects of the invention, the drill string may embody a plurality of stabilizers and drill collars to provide a stabilized bore. As shown in Fig. 8, a plurality of stabilizers S are alternately arranged with drill collars C between the lower end of a drill string D and a drill bit B. This arrangement causes the stabilizers to maintain the drill collars centrally in the bore or hole H. Hence, for all practical purposes, a straight hole will result. If the'hole H is on a slant, such stabilization will maintain the angle of slant.

When it is desired to increase the angle in a slanted or directional bore H, a stabilizer S is placed immediately above the bit B or a short distance thereabove. The hole part H shows the original slant and the part H" the increased slant, it being evident that the reaming or stabilizing fins or ribs 12 provide a point of fulcrum at F because the drill collar C, now at the side of the hole, brings the fins into direction-changing engagement with the bore part H". If a greater rate of angular change is desired, the collar C may be omitted and the stabilizer immediately adjacent to the bit may be connected directly to the lower end of the drill pipe D. The increased rate results from the greater flexibility of the pipe D with respect to collar C.

In order that the angle of a slanted hole be lessened or a crooked hole straightened, a stabilizer S may be placed some distance above the bit B. Two or more drill collars C may be interposed between the bit and the stabilizer, creating a mass that, through the force of gravity, causes a drilling action that bends the bore H back toward the vertical as indicated by the arrow A.

Since dog legs are generally caused by a too rapid change in the direction of the bore hole, stabilizers keep the axis of the drill collar string in a straight line and reduce the tendency for rapid directional changes of the bit. Also, stabilizers reduce fatigue failures by centering the drill collars in the hole, thereby decreasing bending stresses in the tool joints. Drill collar wear is also reduced for this reason.

While the foregoing has illustrated and described what are now contemplated to be the best modes of carrying out the invention, the constructions are, of course, subject to modification without departing from the spirit and scope of the invention. It is, therefore, not desired to restrict the invention to the particular forms of construction illustrated and described, but to cover all modifications that may fall within the scope of the appended claims.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

1. In a tool of the character described, adapted to be incorporated in a drill string; an elongated cylindrical mandrel having upper and lower annular shoulders, a cylindrical reaming collar loosely and slidably mounted on said mandrel, a key on said mandrel substantially midway between said shoulders, said collar having a first recess wider than said key, receiving said key, and provided with a side face engageable with a side face of said key, said collar having at least one keyway therein extending axially from one end of said recess and circumferentially offset from said side face of said recess, said side face of said recess having axially spaced and oppositely slanted cam surfaces, said side face of said key having axially spaced cam surfaces complementary to but of less length than said cam surfaces of said recess, the length of said collar being greater than the distance from said key to either of said shoulders whereby said key is always in rotary driving relation to said collar.

2. A tool as defined in claim 1 including a second recess in said collar identical to and axially spaced from said first recess, said keyway extending between said recesses.

3. A tool as defined in claim 1 wherein said recess is substantially midway between the ends of said collar, said keyway extending to one end of said collar, and a second keyway extending axially from the other end of said recess to the other end of said collar.

References Cited in the file of this patent UNITED STATES PATENTS 2,029,579 McCullough Feb. 4, 1936 2,212,067 Holfoss Aug. 20, 1940 2,501,025 Burris Mar. 21, 1950 2,665,887 Shelton Jan. 12, 1954 

